This S40 Stage could be better configured to reduce drag and improve handling


Fig 2

Fig 2

Dive Rite Nomad LT

Sidemount Harness

Since our last meeting in these pages I have traveled in a westerly direction to the UK and USA to expand my knowledge and technical know how of Side-mount diving.

In the past we looked at some of the basic conceptual ideas of side-mounting along with the advantages/disadvantages of the system.

I left you with a promise that we would be revisiting the world of side-mount diving in later blogs, and so here we go, deeper into side-mount.

I previously explained some of the basics about side-mounting cylinders. This quarter we will look at how I connect and rig my cylinders. This is not to say that this is the only way to connect and rig your system. For me personally the system I use fits a number of different diving environments I may find myself in, in my diving exploits, and may help you develop your own ideas for your rig.

I am currently using two different harnesses/wing systems, the Dive Rite Nomad XT for situations where I need 4 cylinders and a bigger lift capacity, and the new Nomad LT. The LT is a fantastically small, streamline and robust wing. Both systems are designed and developed by Dive Rite, The nomad LT is exceptional for cave/wreck diving and getting through small gaps due to its incredibly low volume.  I have carried three s80 cylinders on the LT wing in salt water with no problems while wearing a 5mm wetsuit (However be advised this is over the recommendation from Dive Rite for this specific system).

I have enclosed a picture of how your cylinders should NOT look when carrying an S40 stage so you can get a feel for what to look out for when rigging your primary and stage cylinders (Stage cylinders  should only be carried by Tec Sidemount qualified divers). We will be looking at stage rigging for side-mount in future articles. My personal view is that your cylinders should lay flat inline with your torso and sit directly under your arm pit. You see a lot of side-mount beginners with their cylinders floating up at a 25-45 degree angle and producing drag.

I have generally been using Steel cylinders when side-mount diving in the UK and Florida.

Steel cylinders sit just right due to their negative weight. The Aluminium S80 cylinders are more common to this region  (it is rumoured that Al Boom Diving will be getting a batch of steel cylinders in  stock within the next month or two). The problem with the S80s is that they get positively buoyant as you breath them down. For this reason I incorporate 2 small 0.5kg trim weights on the cam band. These weight are less bulky than a single 1kg block. The trim weight on the cam band will make the cylinders lay in a flat streamlined orientation down to a remaining 60-70Bar of tank pressure, depending where you clamp the cam band. I tend to clamp the bottom of the band approximately 12cm from the bottom of the tank. 

I have tried almost all the configurations and set ups on the market. Some CE certified and some not.  The thing that is most striking about side-mount diving is that there are a lot of choices to make with regard to getting the right set up for you. You have to think what sort of diving you are going to be doing and what is the worst case scenario for that dive.

I have made my side-mount rig global. By this I mean that I can travel anywhere in the world and be equipped with almost any type of cylinder that a commercial dive operator wants to give me, and still be able to dive with my side-mount system with no problems. The secret to this is in cylinder rigging. I construct my own cylinder rigs from 4/5mm Dyneema cord, two large P-Clips, one cam band per cylinder, a 2 inch metal slide, and two hose retainers. The Dyneema cord can be purchased on a roll from specialist outdoor stockist but you can also use military parachute cord as a very good and cheeper alternative. Its a good idea to carry some spare two inch stainless steel slides  and a couple of large ring Number Three P-clips in your save a dive box when you travel. The two inch slides are used to hold the bottom P-Clip in place on the cam band. The most expensive part of the system, and an area that you should not try to save money is the cam band that holds the cylinder. I like to use good quality metal buckles that are attached to well stitched webbing/band.

There are two main ways to connect your cylinder valves to your wing. The simplest way is with a loop of elastic bungee that comes from just bellow your shoulder blade at the back of your wing, and goes round the neck of one cylinder valve (under the valve knob) and clips to a D ring on your shoulder strap.

The other method is the Ring Bungee system. For more information on the ring bungee system take a look on the Dive Rite sight.

I currently connect my cylinders to my harness with the Ring Bungee system designed by Lamar Hires and the Dive Rite Team. I like this system for a number of reasons. When you are out of the water and the cylinders are connected, the cylinders hang on the P-clip and Maillon (a Maillon is a simple stainless steel screw gate karabiner used generally by climbers, cavers and mountaineers and comes in various sizes). The P-clip and Maillon connect the ring and bungee to the Sidemount wing. I have recently taken to replacing this Maillon with Dyneema cord so that your cylinder can be cut free in an emergency situation.  The bungee usually attaches at the shoulder blade area of the wing. I find the ring bungee system better than using just elastic bungee loops, because if you have to move around on the surface/boat  with your cylinders attached then your cylinders tend to bounce and intern stretch/break the elastic bungee when using just the elastic loop system. Another added advantage of the ring bungee system is that if the bungee does fail then the P-clip and Maillon connected to the ring will remain connected thus keeping your cylinder attached. The set-up of the ring bungee hinges on having your first stage regulator facing forward and a choker (a choker is a cord / webbing ring) around the neck of the cylinder valve. The P-Clip at the top of the spine of your cylinder rig then clips into this choker see Fig 3.

The bottom of my cylinders are connected using the tail of the cord after it has been larksfooted to a P-clip, and then pasted though the cam band webbing in the metal slide. This P-clip then connects the cylinder rig to the butt rail on your side-mount wing. As I mentioned earlier you may not like this system but it has worked for me in a number of very challenging cave dives and wreck penetrations in both warm and cold water.

I hope this article has been useful to some of you and I welcome your feedback and questions.

Jon F

Fig 3

Fig 1

Deeper into

         Side-mount Diving

By: Jon F